Headlines: Inheritance of mitochondrial DNA. Coffee and Parkinson’s disease. Sending your name and a message to the New Horizons spacecraft. Winds on Mars. Water on Asteroids.

Feature: Titan (starts at 8:55) The solar system has so many different worlds that come in all shapes and sizes and histories, from boiling hot Mercury and Venus to icy Pluto and the Kuiper belt. Such extreme alien worlds are exciting, but perhaps the places that catch our imaginations the most are the ones that are more familar – perhaps with the hope of humans one day visiting there and even living there. So we think of places that have atmospheres and have – or once had – liquid water. But then there are those places that live in what you might call “the uncanny valley” between familiar and alien, and perhaps Saturn’s moon Titan fits into that category, with an atmosphere (but not one that you would want to breathe) and lakes (but not ones you would want to swim in).

The Cassini mission to Saturn launched 20 years ago, on October 15, 1997. It took seven years to reach Saturn, and has been orbiting and intensely studying Saturn ever since…until last week when the mission ended in a final dive into Saturn’s atmosphere. The mission studied Saturn, its famous rings, and its many moons using a suite of instruments that observed a broad range of wavelengths from ultraviolet, to visible, infrared, and radio as well as examining dust, charged particles, and magnetic fields. It also delivered the Huygens probe that descended through the atmosphere of Saturn’s giant moon, Titan.

With graduation season is upon us, or in many cases in the rearview mirror, today’s edition of How on Earth is the first of a two-part “Graduation Special”. Our guests in the studio today are scientists who recently graduated with – or soon will receive – their Ph.D. They talk about their thesis research, their grad school experiences, and what they have planned next.

David Horvath – Colorado School of Mines, Department of Geophysics
Topic: Planetary Hydrology: Implications for the Past Martian Climate and Present Titan Lake Hydrology Using Numerical Models of the Hydrologic Cycles on Titan and Mars

Titan, a moon of Saturn, rises above the rings of Saturn. Image courtesy of NASA/JPL

Beyond Earth (start time 5:10) Many have dreamt of colonizing other planets. It’s been a staple of science fiction for decades. Most often, people imagine creating a colony of humans on Mars, where people would live on a cold, dry planet with a thin, unbreathable atmosphere. Mars, however, may not be the best destination for future human colonization. In fact, Titan, a moon of Saturn, may hold greater hope for extending humanity’s presence in the solar system. Either way, humans face tough but surmountable challenges as we move beyond Earth. As a planetary scientist, Dr. Amanda Hendrix is actively involved in the scientific research and future mission planning that will enable humans to settle on other planets. She’s the co-author, with Charles Wohlforth, of the new book Beyond Earth: Our Path to a New Home in the Planets. Listen to How On Earth’s Alejandro Soto’s interview with Amanda Hendrix, where they discuss the opportunities and challenges for human space exploration.

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